Heat exchangers wherein fluids are made to pass through two spiral passages and heat is exchanged between these fluids (the heat exchanger is hereinafter referred to as xe2x80x9cspiral heat exchangerxe2x80x9d for convenience) are known. For example, Japanese Laid-open Patent Application (Kokai) No. 56-82384 discloses a heat exchanger comprising two spiral passages. Fluids are made to pass through the respective passages in counter directions so as to exchange heat through the walls of the passages. A similar heat exchanger is also described in xe2x80x9cHigh Performance Heat Exchanger Data Bookxe2x80x9d, published by Energy Saving Center, page 195.
With the conventional spiral heat exchangers, heat exchange is carried out while passing the fluids through the entire passages, they have an advantage that the efficiency of heat exchange is high. However, since the fluids are made to enter the passages from the start and end points thereof, respectively, and made to pass all the way to the respective outlets, the pressure loss (air-flow resistance) is large, so that the amount of the fluid which can be processed in a unit time is small, and so the throughput is small. To increase the throughput, it is necessary to introduce the fluids into the passages with a high pressure, so that a strong motor is necessary and the electricity consumption is large.
Accordingly, an object of the present invention is to provide a heat exchanger having a high efficiency of heat exchange comparable to the conventional heat exchangers utilizing spiral passages, while having a smaller pressure loss (air-flow resistance) than the conventional heat exchangers of this type, and to provide a method for producing the heat exchanger, as well as to provide a dehumidifier utilizing the heat exchanger.
The present inventors have determined that by discharging the fluid after passing the fluid through the spiral passage for less than one turn only, the overall heat exchanging efficiency is as high as those of the conventional spiral heat exchangers, while the pressure loss (air-flow resistance) is reduced and so the throughput is largely increased, thereby completing the present invention.
The present invention provides a heat exchanger comprising a first spiral passage, a second spiral passage formed along said first passage, which is adjacent to said first passage via walls; first and second end plates which cover both end faces of said first and second passages, respectively; a first passage inlet consisting essentially of a group of openings formed in a first region continuous along radial direction in said first end plate, said openings are being open only to said first passage; a first passage outlet consisting essentially of a group of openings formed in a second region continuous along the radial direction in said first or second end plate said openings being open only to said first passage; a second passage inlet consisting essentially of a group of openings formed in a third region continuous along the radial direction in said first or second end plate, said openings being open only to said second passage; and a second passage outlet consisting essentially of a group of openings formed in a fourth region continuous along the radial direction in said first or second end plate, said openings being open only to said second passage; said first passage being tightly closed except for said first passage inlet and said first passage outlet; said second passage being tightly closed except for said second passage inlet and said second passage outlet; a first fluid entering said first passage from said first passage inlet and being discharged from said first passage outlet after passing through said first passage for less than one turn; a second fluid entering said second passage from said second inlet and being discharged from said second passage outlet after passing through said second passage for less than one turn whereby heat is exchanged between said first and second fluids through said walls during said first and second fluids passing through said first and second passages, respectively.
The present invention also provides a heat exchanger comprising a first spiral passage; a second spiral passage formed along said first passage, which is adjacent to said first passage via walls; first and second end plates which cover both end faces of said first and second passages, respectively, a first passage inlet consisting essentially of a group of openings formed in a first region continuous along the radial direction in said first end plate, which openings are open only to said first passage; a first passage outlet consisting essentially of a group of openings formed in a second region continuous along the radial direction in said first or second end plate, which openings are open only to said first passage; a second passage inlet consisting essentially of a group of openings formed in a third region continuous along the radial direction in said first or second end plate, which third region is located at an area other than said first and second regions, which openings are open only to said second passage, and a second passage outlet consisting essentially of a group of openings formed in a fourth region continuous along the radial direction in said first or second end plate, which fourth region is located at an area other than said first and second regions, and and formed in the first or second end plate other than the one in which said second passage Inlet is formed said openings being open only to said second passage; said first passage being tightly closed except for said first passage inlet and said first passage outlet; said second passage being tightly closed except for said second passage inlet and said second passage outlet; a first fluid entering said first passage from said first passage inlet and discharged from said first passage outlet after passing through said first passage for less than one turn; a second fluid entering said second passage from said second inlet and discharged from said second passage outlet after passing through said second passage in axial direction whereby heat is exchanged between said first and second fluids through said walls during said first and second fluids passing through said first and second passages, respectively.
The present invention further provides a heat exchanger comprising a first spiral passage; a second spiral passage formed along said first passage, which is adjacent to said first passage via walls; first and second end plates which cover both end faces of said first and second passages, respectively; a first passage inlet consisting essentially of a group of openings formed in a first region located at an outer half or about an inner half of an area continuous along the radial direction in said first end plate, said openings being open only to said first passage; a first passage outlet consisting essentially of a group of openings formed in a second region located at an outer half of an area continuous along the radial direction in said first or second end plate when said first passage inlet is located at said outer half of said radially continuous area, or located at an inner half of an area continuous along the radial direction in said first or second end plate when said first passage inlet is located at said inner half of said radially continuous area, which openings are open only to said first passage; a second inlet of said first passage consisting essentially of a group of openings formed in a third region located at an outer half of an area continuous along the radial direction in said first or second end plate when said first passage inlet is located at said inner half of said radially continuous area, or located at an inner half of an area continuous along the radial direction in said first or second end plate when said first passage inlet is located at said outer half of said radially continuous area, which openings are open only to said first passage; a second outlet of said first passage consisting essentially of a group of openings formed in a fourth region located at about an outer half of an area continuous along the radial direction in said first or second end plate when said second inlet of said first passage is located at said outer half of said radially continuous area, or located at an inner half of an area continuous along the radial direction in said first or second end plate when the second inlet of said first passage is located at said inner half of said radially continuous area, which openings are open only to said first passage; a second passage inlet consisting essentially of a group of openings formed in a fifth region continuous along the radial direction to said first or second end plate, said fifth region being formed in an area other than said first to fourth regions, said openings being open only to said second passage; a second passage outlet consisting essentially of a group of openings formed in a sixth region continuous along the radial direction in said first or second end plate, said sixth region being formed in an area other than said first to fourth regions, and being formed in the first or second end plate other than the one in which said second passage inlet is formed, which openings are open only to said second passage, and a third passage which air-tightly connects said first outlet of said first passage and said second inlet of said first passage; said first passage being tightly closed except for said first and second inlets of the first passage and said first and second outlets of the first passage; said second passage being tightly closed except for said second passage inlet and said second passage outlet; a first fluid entering said first passage from said first passage inlet and entering said third passage from said first passage outlet after passing through said first passage for less than one turn, then entering said first passage from said second inlet of said first passage, and discharged from said second outlet of said first passage after passing through said first passage for less than one turn, a second fluid entering said second passage from said second inlet and discharged from said second passage outlet after passing through said second passage in an axial direction, whereby heat is exchanged between said first and second fluids through said wall while said first and second fluids pass through said first and second passage, respectively.
The present invention still further provides a method for producing the heat exchanger of the present invention comprising the steps of holding first and second end plates in a parallel, in which said openings are formed, each of which having a spiral ridge; stacking two films composed of a material having flexibility and elasticity; and winding said films such that each film contacts each ridge while bending said film such that central portion in the direction perpendicular to longitudinal direction of said film protrudes in the outer direction of said spiral. The present invention further provides a dehumidifier using the heat exchanger of the present invention.
The present invention provides a novel heat exchanger in which the pressure loss is small and the throughput is large and the heat-exchanging efficiency is as high as that of conventional spiral heat exchanger. By the production method according to the present invention, the spiral heat exchanger according to the present invention may be produced inexpensively and in a large quantity. Further, by the present invention, a dehumidifier is provided having a high heat-exchanging efficiency, and a low electricity consumption.